Helicity amplitude analysis of $\chi_{cJ} \rightarrow \phi\phi$

TL;DR

This study measures the decay rates and polarization parameters of $ ext{chi}_{cJ} ightarrow ext{phi} ext{phi}$ decays using a large dataset, providing the most precise branching fractions and first-time polarization analysis.

Contribution

It presents the most precise measurements of branching fractions and the first helicity amplitude analysis of $ ext{chi}_{cJ} ightarrow ext{phi} ext{phi}$ decays.

Findings

Branching fractions are measured with high precision.

First polarization parameters for $ ext{chi}_{cJ} ightarrow ext{phi} ext{phi}$ are determined.

Helicity amplitude analysis provides new insights into decay dynamics.

Abstract

Using (447.9 $\pm$ 2.3) million $\psi$(3686) events collected with the BESIII detector, the decays of $\chi_{cJ} \rightarrow \phi\phi$ ($J$=0, 1, 2) have been studied via the decay $\psi(3686)\rightarrow\gamma\chi_{cJ}$. The branching fractions of the decays $\chi_{cJ} \rightarrow \phi\phi$ ($J$=0, 1, 2) are determined to be $(8.48\pm0.26\pm0.27)\times10^{-4}$, $(4.36\pm0.13\pm0.18)\times10^{-4}$, and $(13.36\pm0.29\pm0.49)\times10^{-4}$, respectively, which are the most precise measurements to date. From a helicity amplitude analysis of the process $\psi(3686) \rightarrow \gamma \chi_{cJ}, \chi_{cJ}\rightarrow \phi\phi, \phi\rightarrow K^{+}K^{-}$, the polarization parameters of the $\chi_{cJ} \rightarrow \phi\phi$ decays are determined for the first time.